Broken Ring Land on a Forged Motor, Recommendations on

[Hysteria]

I have a built and Mommoth Blown (18#'s) 3V with a Livernois Stroker Assembly rated to 900HP. The car has a smoking issue at 3000RPM, but not at startup or at WOT. Pulled the plugs and found oil on one of them, through the use of a bore cope, found that one of the ring lands on the Mahle Pistons is broken.

Question, for a High Horsepower/Boosted motor (600RWHP+):

1. What are you guys using for pistons (JE, CP, Diamonds)?

2. How much over size can you go on a 4.6 (.010'', .020'' )?

3. Any recommendations on who to purchase through?

 

[Marc s]

I use CP 2618 alloy pistons with a 4-5 thousands piston to cylinder clearance. You do need to widen out the top ring to .0055-.006 per in. of bore diameter (to be totally safe). Current thinking is that the second ring gap should be opened up slightly larger that the top ring gap. This allows the pressure that gets into the ring land area to be relieved through the second ring gap instead of possible lifting the top ring and compromising the top ring's sealing ability. Remember the function of the second ring is 20% compression control and 80% oil control. This is why a second ring with taper face and reverse twist is typically used in high performance applications.

 

[retfr8flyr]

I have always been partial to JE pistons and run them currently but CP 's are also very good. The most I would bore the block with a supercharger is .020 over. It's hard to find .010 over pistons, without going custom made but if .010 over will clear up any cylinder damage that's what I would try and go with. The stronger the cylinder walls the better.


Earl

 

[lito]

Any 2618 stuff will be better than the 4032 you have now.

Almost any brand piston properly tuned will hold well, I incline for Diamond.

You maybe lucky enough to have material for 3.552 piston on 2618 as they will need more tolerance, hope it is that way, once you have things out only measuring will tell, if not .020 is in order.

 

[GB10]

I agree with Lito that you should tear it down and check the bores for any gouges from the broken ring land. Also, use a dial bore gauge and check for straightness and bore size. I would only bore it over if it needs to be; otherwise, stick with stock bore.

What happened when the ring land broke?

 

[joedls]

If you decide on CP, I have a set for sale.

http://s197forum.com/forum/showthread.php?t=71574

 

[stkjock]

Diamond

Mike@ L&M has a custom design, as I recall with a thicker dome to help protect the rings

http://lmengines.com/product/821LM

 

[SteveP]

I have a built and Mommoth Blown (18#'s) 3V with a Livernois Stroker Assembly rated to 900HP. The car has a smoking issue at 3000RPM, but not at startup or at WOT. Pulled the plugs and found oil on one of them, through the use of a bore cope, found that one of the ring lands on the Mahle Pistons is broken.

Question, for a High Horsepower/Boosted motor (600RWHP+):

1. What are you guys using for pistons (JE, CP, Diamonds)?

2. How much over size can you go on a 4.6 (.010'', .020'' )?

3. Any recommendations on who to purchase through?

1. Manley H beam rod w/ ARP bolts attached to a custom Ross piston (.20 bore) with custom rod bearings (was built by 2Nasty Racing/ Dez Racing)

2. On a standard block, .30 is as high as I would go.

3. Their are many engine builders out there and many do great work. I would be more then happy to talk to ya about some options and different directions you could go.

 

[Hysteria]

Thank you for all of the input guys. As far as what happened, I couldn't tell you. I've kissed the revlimiter a few times at the track do to the 5R55 giving me trouble, and I assume that's where it happened.

Once the shop gets the motor torn down, I'll fill you guys in more. I guess I'll start looking towards the 2618 Pistons.

Joedls, I'd be inclined to get yours, but sisn't I read that your pistons were for a nonstroked motor? I don't know the differences there so forgive me if I sound ignorant.

 

[SteveP]

The best piston's IMO out there for 3v's are Ross (custom), Diamond (custom) and JE. I have run all 3 and had the best results with the Ross. But with Diamond and JE, I have NO complaints at all. But the JE and Diamond were just off the shelf pistons and I wanted something more. For what your going, any on the shelf piston from these companies will work great!! And what I mean by on the shelf is already made. Just to clarify to sum.


now for another way that works great and does last (with high horsepower) is Manley. Wont break the bank like the other ones listed either.

 

[stkjock]

I have run all 3 and had the best results with the Ross.

Steve - can you be more specific on that comment. What is the benchmark to say the results were better, what instrumentation was used, how was it documented.

 

[SteveP]

What I mean by better is each piston I've used was designed around the set up I went. First piston (JE Pistons) was used when I had the 8:5:1 compression with the vortech. When that motor had the issues from the meth pump failing on me leaning out the motorand many other things. (this happened back in 09) I went with Diamond pistons and raised the compression to 9:5:1 (as well as many other items) Car made great power! With all the other add-ons, Motor could run up to 6800 and be fine. Last winter (still up north) I wanted to make sure the motor could handle 7500rpms and then, I planned on swapping to a Procharger F1C. I also wanted to up the power level. So 2Nasty Racing (engine builder) went to town with the block. He re-did all the wells, and swapped out the H beams with reg bolts to the ARP ones. Each piston had a custom rod bearing and they used Ross pistons.

So what I mean by I have seen the best is that with the route I went with the turbo over the blower, I can pull up higher rpms safely, Not worry about making 750ish rwhp and over 800lbs of trq. My bottom end is safe up to 1000 if I choose too but never ever will.


Now could the Diamond, JE, CP, Manley, ect do this..... YES!!! I personally love Diamond pistons and will swear by them. My engine builder will agree with me too. He wanted to see how the Ross would do and I am very pleased so far.

Hope this helps

 

[joedls]

Joedls, I'd be inclined to get yours, but sisn't I read that your pistons were for a nonstroked motor? I don't know the differences there so forgive me if I sound ignorant.

You're correct. My pistons are for standard stroke, not a stroker motor.

 

[lito]

Diamond

Mike@ L&M has a custom design, as I recall with a thicker dome to help protect the rings

http://lmengines.com/product/821LM

^+1

 

[Hysteria]

Thanks guys, I'll check it out!